The CALGB is comprised of 26 academic medical centers and over 200 affiliated community hospitals joined in the pursuit of improved cancer treatment and better understanding of tumor biology and cancer treatment outcomes via the conduct of controlled clinical trials. Over 4,000 members of the Group including oncology physicians, radiologists, pathologists, statisticians, clinical research associates, oncology nurses, pharmacists, health outcomes researchers, and basic scientists participate in these studies. From 25-30 Phase III protocols are active at any one time, along with phase II and phase I studies that provide preliminary data required for the appropriate design of large scale randomized trials. Multidisciplinary disease committees of the Group design and implement protocols for the treatment of patients with leukemia, lymphoma, breast, respiratory, Gl and GU cancer. Modality committees, including Leukemia Correlative Sciences, Imaging, Pharmacology and Experimental Therapeutics, Surgery, Transplant, Cancer in the Elderly, Cancer Control and Health Outcomes, and Oncology Nursing provide expertise that enhances the contribution of these disciplines to CALGB studies. Scientific resources committees, including Clinical Research Associates, Pathology and Radiation Oncology, provide essential quality assurance and training activities for the Group. Major areas of emphasis in CALGB include development of innovative treatments for patients with cancer; studies of molecular predictors of prognosis and response to therapy; studies of the pharmacokinetics, pharmacodynamics and pharmacogenetics of new and established anticancer drugs; evaluation of minimally invasive surgical techniques and novel imaging technologies; determining the cost and cost-effectiveness of new cancer therapies; evaluating the impact of cancer and its treatment on the quality of life of cancer patients and their caregivers; developing new strategies for cancer prevention; and addressing the needs of special populations, particularly minorities and the elderly. A new core facility in cancer imaging was established to provide central review and archiving of PET and CT images and to set standards for image acquisition and transmission at CALGB institutions. Three established biorepositories collect, archive and distribute frozen and paraffin-embedded solid tumor tissues, leukemia cells, plasma, serum, urine and DNA for correlative science studies.